Apparatus for producing webs of reconstituted tobacco

ABSTRACT

Apparatus for the production of webs of reconstituted tobacco comprises a set of endless steel belts having immediately adjacent coplanar upper stretches which receive a mass of moist tobacco containing material forming thereon a layer which is thereupon transported through a drying zone to be converted into a web of reconstituted tobacco. The drying zone accommodates a single drying unit wherein chambers which discharge heated air alternate with chambers which collect moisture-laden air.

United States Patent lnventor Appl. No.

Filed Patented Assignee Priority Heinz Gretz Hamburg-Bergedorf. Germany 790,227

Jan. 10, 1969 July 6, 1971 Hauni-Werke Korber 8: G. Kg. Hamburg-Bergedorf, Germany Jan. 18, 1968 Germany APPARATUS FOR PRODUCING WEBS 0F RECONSTITUTED TOBACCO 23 Claims, 6 Drawing Figs.

Int. Cl

F26!) 19/00 Field of Search References Cited UNITED STATES PATENTS Dahl 687,033 11/1901 Kester 34/236 1,050,400 l/l913 Steele... 198/190 2,229,546 1/1941 Bogaty 131/136 2,246,914 6/1941 CraggsH. 131/136 2,429,100 10/1947 Loose... 198/190 2,656,841 10/1953 Gurley 34/68 2,677,336 5/1954 Spaoner 34/66 2,821,030 1/1958 Bogaty 34/236 3,371,670 3/1968 Camenisch 131/136 3,396,734 8/1968 Jansson 131/140R 3,402,479 9/1968 Holm 334/66 Primary Examiner-Wi11iam J. Wye Attorney-Michael S. Striker ABSTRACT: Apparatus for the production of webs of reconstituted tobacco comprises a set of endless steel belts having immediately adjacent coplanar upper stretches which receive a mass of moist tobacco containing material forming thereon a layer which is thereupon transported through a drying zone to be converted into a web of reconstituted tobacco. The drying zone accommodates a single drying unit wherein chambers which discharge heated air alternate with chambers which collect moisture-laden air.

PATENTEDJUL 6197! 3,590,493

sum 2 OF 4 WVENTOR HEM/R CA 511,

IWWNM 1 ATTORNEY PATENTED JUL 6 I971 sum 3 OF 4 BACKGROUND OF THE INVENTION back of such apparatus is that their relatively wide steel belts are extremely sensitive, particularly to repeated changes in temperature which cause warping and other forms of deformation. Moreover, the initial cost of such wide belts is very high, to a considerable extent because the ends of a wide steel belt must be welded to each other with utmost care, normally in a protective atmosphere and by resorting to complicated, costly and bulky welding equipment. Furthermore, the welding often causes localized stressing of a wide belt so that such belt is even more likely to undergo deformation in response to repeated heating and cooling, especially if the heating or cooling is not uniform in all zones ofthe belt.

Summary of the Invention One object of the invention is to provide an apparatus for the production of webs of reconstituted tobacco with a novel conveyor assembly which is cheaper, longer lasting, more reliable and more resistant to thermal stresses than presently known conveyor assemblies.

Another object of the invention is to provide a novel drying unit for use in the improved apparatus.

A further object of the invention is to provide the apparatus with novel tightening means for the endless travelling part or parts of the conveyor assembly.

An additional object of the invention is to provide an ap paratus wherein the expulsion of moisture from a mass which forms a travelling layer of reconstituted tobacco can be carried out in a small area so that the length of the conveyor assembly can be reduced well below the length of conveyor assemblies in conventional apparatus.

One feature of my invention resides in the provision of an apparatus for the production of webs of reconstituted tobacco which comprises conveyor means including a plurality of relatively narrow travelling endless belts having upper stretches, feeding means for supplying onto the upper stretches a moist tobacco-containing mass so that the mass forms at least one layer which travels lengthwise with the belts, and drying means for expelling moisture from the layer to thereby convert the layer into at least one web of reconstituted tobacco. The belts may consist of rustproof steel and the conveyor means preferably comprises a common drive for all of the belts.

In accordance with a second feature of my invention, the drying means comprises a single drying unit which is installed at a level above the upper stretches of the belts and.comprises at least one first chamber adjacent to the path of the layer, at least one second chamber adjacent to the first chamber, a heat exchanger or analogous means for supplying heated air to the first chamber whereby such air expels moisture from successive increments of the travelling layer and is enriched with moisture, and means for drawing the thus enriched air into and from thesecond chamber. The means for drawing enriched air may comprise a blower whose suction side is connected with the second chamber and whose pressure side is connected with the heat exchanger.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved apparatus itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 (composed of FIGS. 1a and lb) is a perspective view of an apparatus which embodies one: form of the invention, a portion of the drying means and a portion of the frame being broken away for the sake of clarity;

FIG. 2 is an enlarged fragmentary longitudinal vertical sectional view as seen in the direction of arrows from the line Il-ll of FIG. lb;

FIG. 3 is a top plan view of the drying means, with the upper insulating panel of the drying means broken away;

FIG. 4 is a transverse vertical sectional view as seen in the direction of arrows from the line IV-IV of FIG. 3; and

FIG. 5 is a fragmentary longitudinal vertical sectional view as seen in the direction of arrows from the line V-V of FIG. la.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The apparatus of FIG. 1 is utilized. for the production of a continuous web of reconstituted tobacco. The apparatus includes parts which are installed at several stations including a first or feeding station A at which a moist tobacco-containing mass is fed onto the upper stretches 21a, 21b, 21c, Zlld, Zle of a group of endless belts la, lb, lc, Ld, la, a drying station B where the surplus of moisture is expelled from the mass which forms on the upper stretches of belts la-le a layer 500 of constant or nearly constant thickness, a separating or removing station C where the web 50b is separated from the belts la-le, and a tightening station D where the lower stretches a, 80b, 80c, 80d, 80e of the belts 'la-lle are subjected to requisite (preferably constant) tension. The belts la-- le consist of high-quality rustproof steel and are trained over a pair of rollers 2 and 3. The shaft 4 of the roller 2 carries a sprocket wheel 6 driven by an endless chain 7 which is trained over a second sprocket wheel 11 on the output shaft 8 of an electric motor 9. The parts 4 to ill constitute a drive for the roller 2 and hence for all of the belts.

The station A accommodates a feeding unit which is best shown in the right-hand portion of FIG. 1 and in FIG. 5. This feeding unit comprises a receptacle or tank 12 which accommodates partitions 10a, 10b, 10c, 10d servingto subdivide its interior into five compartments 13a, 13b, 13c, 13d, l3e each of which is adjacent to the upper stretch of one of the belts lais. The tank 12 is provided with brackets or carriers lSa, 15b which are affixed to the frame members 78a, 78b of the apparatus by bolts 20a, 20b. The bottom part of the tank 12 is open and is partially sealed by the upper stretches Zia-21c of the belts 1a--le in such a way that the compartments 13al3e of the tank define with the corresponding belts a series of coplanar gaps or outlets 17a, 17b, 17c, 17d, 17:: for discharge of moist tobacco-containing mass toward the drying station B. TI-le means for supplying tobacco-containing mass into the tank 12 comprises a single main supply conduit 14 which has a manifold 14a discharging into five vertical pipes 16 a, 161;, 16c, 16d, 162 each of which delivers moist mass to one of the compartments l3a-l3e. The width of the gaps l7a-ll7e is somewhat less than the width of the respective belts la-le so that the marginal portions of the belts do not receive the mass immediately at the station A. The mass spreads automatically and covers the full width of the conveyor assembly including the belts 1a--le.

The feeding unit at the station A further comprises a metering device for insuring that each compartment is filled to a predetermined level. This metering device includes overflow openings (only the opening 18b shown in FIG. 2) which discharge the surplus into a return conduit 19 for delivery back to the main source which delivers moist tobacco-containing mass to the supply conduit 14.

The belts lale are closely adjacent to and abut against each other. Their upper stretches 2la2le carry the layer 50a of moist tobacco mass toward, through and beyond the drying station B. These upper stretches 2la2le are located in a common (preferably horizontal) plane. The drying station B accommodates a single drying unit 22 which is mounted at a level above the upper stretches Zia-21a and is constructed in accordance with a novel and advantageous feature of the present invention. Its details are shown in FIGS. 3 and 4. In

FIG. 3, the top panel of insulation around the internal space of the drying unit 22 is broken away for the sake of clarity. The just mentioned space accommodates a set of transversely extending first chambers 23 for hot gaseous fluid (preferably air) which receive heated air from the outlet of a heating device here shown as a heat exchanger 24. The inlet of the heat exchanger 24 is connected with a header 26 which is connected with the pressure side 28 of a blower 29 by a pipe 27. THe suction side 31 of the blower 29 is connected with second chambers 32 for spent moisture-laden air which alternate with the aforementioned first chambers 23 and have open undersides located directly above the upper stretches of the belts lale. The bottom walls 33 of the chambers 23 are provided with air discharging apertures 34. These bottom walls are disposed above the upper stretches of the belts la 1e. The suction side 31 of the blower 29 is further connected with a pipe 36 which is open to the atmosphere and accommodates a regulating valve 37 adjustable by a handle 30. The pressure side 28 of the blower 29 is connectable with the atmosphere by a second pipe 38 which accommodates a regulating valve 39. The latter is adjustable by a handle 35. The coils 40 of the heat exchanger 24 contain a circulating heating medium (for example, oil) which is supplied by a conduit 47 and returned for reheating by a conduit 48.

The novel belts lale can be used with equal advantage in apparatus wherein the drying station accommodates a different drying unit or a set of different drying units. For example, the drying unit 22 can be replaced by a drying unit which heats the mass of tobacco-containing material with infrared rays or the apparatus may employ a drying unit which is a combination hot air heater and infrared heater. Furthermore, the drying station B can accommodate a conventional contact heater for the belts lale in addition to or as a substitute for a hot air drying unit or infrared drying unit.

The mass which fills the compartments 13a13e to a predetermined level comprises finely comminuted tobacco particles dispersed in water which contains other well-known ingredients. The mass is of pulpy consistency and its viscosity is sufficiently low to insure that it forms a series of layers after it leaves the gaps 17a-17e. The finished web 50b can be cut into strips or tapes which can be used as inner and/or outer wrappers for cigars, cigarillos or analogous tobacco products.

The parts which occupy the separating station C are shown in the left-hand part of FIG. 1 and in FIG. 5. They include a cooling unit 41, a moistening unit 42, a removing or stripping unit 43, an air discharging unit 44 and a heating unit 46 for the finished product. These units extend along the full length of the roller 2 so that they can treat the material which is transported by the entire conveyor assembly including the upper stretches 21a2le. The cooling unit 41 comprises an elongated nozzle 51 which extends in parallelism with the axis of the roller 2 and is provided with orifices 52 discharging cool air or other suitable gaseous cooling medium toward the upper surface of the web 50b of reconstituted tobacco which emerges from the drying station B. The nozzle 51 receives coolant from a fan 53.

The moistening unit 42 comprises three driven shafts 58, 59, 61 forming part of three roller-shaped applicators 54, 56, 57 which respectively comprise cylinders 62, 63, 64 of sponge rubber or like moisture absorbing material. The cylinder 64 on the shaft 61 dips into a body ofliquid 67 in a vessel 66 and its peripheral surface bears against the peripheral surface of the cylinder 63. The latter bears against the peripheral surface of the cylinder 62 which rolls along the upper side of the web 50b. In this way, the liquid 67 is transported from cylinder 64 to cylinder 63 to cylinder 62 and thence to the web. Such liquid may consist mainly of water which contains a softening agent, for example, glycerine or the like. The shafts 58. 59, 61 carry mating gears (not shown) or are otherwise coupled to each other for rotation in directions indicated by arrows. The prime mover 65 which rotates one of these shafts is preferably an electric motor (see the left-hand portion of FIG. 1).

The removing unit 43 comprises a blade 68 which is biased by one or more springs 69 by way of levers 71 so that its edge bears against the exposed surfaces of the belts la la in a region located substantially at the level of the shaft 4.

The air discharging unit 44 is adjacent to the removing unit 43 and includes an elongated nozzle 73 having orifices 74 which discharge hot air against the web 50b immediately upstream of the edge of the blade 68. The nozzle 73 receives hot air from a source here shown as including a blower 72. The orifices 74 direct jets of air at an acute angle against the exposed surface of the web 50b in the region of the edge of the blade 68. The heating unit 46 comprises an elongated infrared heater 76 which heats the exposed surface of the web 50b downstream of the edge of the blade 68. A takeoff conveyor, here shown as an inclined chute 77, is mounted below the blade 68. This chute transports the web 50b to a further processing station, not shown.

The frame of the apparatus comprises the aforementioned frame members 78a(FIG. 1) and 78b (FIG. 5) which are profiled beams and support the shaft 4 and the shaft of the roller 3. These frame members are mounted on upright beams including those numbered 79a, 79b, and 81a. Plates 70a and 70b are mounted on the frame members 78a, 78b to support the parts of the units 41, 42 at the station C. The units 43, 44 and 46 are mounted on profiled members 75a, 75b which are carried by the frame members 78a, 78b.

The lower stretches a, 80b, 80c, 80d, 80e of the belts la-- 12 travel along the tensioning station D which accommodates a tensioning unit 82. This unit includes a fixed horizontal shaft 83 which carries pivotable levers 84a84e. The arms 86a 86s of the levers 84a84e are provided with adjustable weights 8711-872. The other arms 88a88e of the levers 84a84e are provided with rolls 89a-89e which abut against vertical pins 91a-91e. These pins are fixed to holders 92a- 92c and extend through guides 93a93e. The guides 93a 93a are rigid with a common carriage 94. The undersides of the holders 92a92e are provided with convex liners or pads 96a96e preferably consisting of suitable synthetic plastic material which can be placed into sliding engagement with the lower stretches 80a80e by generating minimal friction. The holders 92a-92e further carry scrapers or doctor blades 97a-97e serving to remove any such tobacco which penetrates between the belts la-1e and can be removed at the upper sides of the lower stretches 80a80e.

The operation:

The tank 12 at the feeding station A receives moist tobaccocontaining material from the supply conduit 14 by way of the manifold 14a and pipes 16al6e. These pipes discharge such material into the respective compartments l3a-13e. The overflow openings (including the opening 18b of FIG. 2) discharge the surplus into the return conduit 19 so that each of the five compartments 13a-l3e is always filledto the same level. The upper stretches 2la-2le of the belts lale trans port a layer 50a of wet tobacco-containing material through the outlets or gaps l7a-l7e and on toward the drying station B. The gaps l7al7e determine the height and the width of the material which is withdrawn from the compartments l3a13e. The drying unit 22 at the station B thereupon expels surplus moisture from successive increments of the layer 50a in the following way:

The blower 29 supplies air to the pipe 27 and thence to the header 26 which admits air into the heat exchanger 24. Such air is caused to exchange heat with oil in the coils 40 and is discharged into the chambers 23 to pass through the apertures 34 in the bottom walls 33 of such chambers and to flow along the top surface of the layer 500. The air withdraws moisture from the layer 500 and is sucked into the chambers 32 to be returned to the blower 29. Such continuous circulation of air insures rapid and very effective drying of the layer 50a. The valve 37 admits to the blower 29 fresh air by way of the pipe 36 to prevent complete saturation of circulating air with moisture. Surplus air is discharged by way of the valve 39 in the pipe 38.

The thus obtained web 50b moves with the upper stretches 2la2le beyond the drying station B and enters the separating station C. If the drying unit 22 is designed to expel more moisture than desired in the ultimate product, or when the web 50b requires moistening in order to facilitate its separation from the belts la-1e, the operator starts the fan 53 which admits cooling air into the nozzle 51 so that such air issues from the orifices 52 and effects further cooling of the web 50b before the latter enters the moistening zone (unit 42). The liquid is applied by the cylinder 62 of the applicator 54 which receives such liquid from the vessel 66 by way of the applicators 57 and 56. The thus moistened web 50b then advances into the range of the edge on the blade 68 and is separated from the belts la-le. The function of the heater 76 is to expel (if necessary) some moisture from the web 50b subsequent to separation from the belts la- 1e. Separation of the web from the belts is facilitated due to the provision of the unit 44 whose nozzle 73 discharges jets of air substantially tangentially to the adjoining convex portions of the belts la-le. The chute 77 conveys the web to a further processing station, for example, to a convoluting station where the web is transformed into a roll of convoluted reconstituted tobacco or to a severing station where the web can be subdivided into narrower strips.

If the drying unit 22 removes just the desired percentage of moisture from the layer 50a, the moistening unit 42 and the heating unit 46 can be omitted or rendered inactive. It is further clear that the moistening unit 42 can be replaced by other types of moistening units, for example, by one having a single row or several rows of orifices which spray a fine mist of atomized liquid onto the exposed surface of the web 5012. Such high-capacity moistening units or sprayers can be used with advantage in large apparatus which are designed to turn out very wide sheets or webs of reconstituted tobacco.

The components of the tensioning unit 82 at the station D insure that each of the belts lalle is maintained under optimum tension. The weights 87a87e tend to pivot the levers 8411-84e in a counterclockwise direction, as viewed in FIG. 1, whereby the pads 96a-96e bear against the lower stretches 80a-80e with a predetermined force. If a lower stretch sags, the moment of the corresponding weight increases because the associated lever turns'in a counterclockwise direction and thereby subjects the sagging belt to higher tensional stresses or at least to stresses whose magnitude does not diminish in response to increased sag of the belt. It is clear that other types of tensioning means (for example, those utilizing springs or analogous biasing means as a substitute for the weights 87a- 872) can be used with equal advantage. If desired, the holders 92a--92e and their pads 96a-96e can be replaced by rollers to further reduce friction between the components of the tensioning unit and the lower stretches 80a-80e.

The number of belts can be reduced below or raised above five. For example, the width of each of these belts may be in the range of centimeters. An important advantage of such relatively narrow belts is that they are much less likely to become twisted or otherwise deformed than a single relatively wide belt. Such twisting ofa relatively wide belt normally oc curs when the belt must repeatedly travel through alternating cooled and heated regions, especially if the differences in tem perature are high. Moreover, independent tensioning of each of the belts 1ale further reduces the likelihood of twisting or other undesirable deformation which normally takes place especially in the marginal zones of a wide belt. The welding of the ends of belts to each other to form endless belts normally takes place in a protective atmosphere, and the expenses involved in welding of relatively narrow belts are but a fraction of expenses which must be incurred in welding of a single relatively wide belt of steel or like metallic material. Furthermore, it is much easier to avoid undesirable localized stressing during welding of relatively narrow belts. Still further, the combined cost of several narrow belts is much less than the cost of a single relatively wide belt of rustproof steel or the like. Also, and since the belts lla-le are tensioned individually and independently of each other, the fact that the upper stretch of each belt might pass through zones which are maintained at different temperatures is of no consequence. Such varying thermal stressing is very damaging to a wide belt.

The aforedescribed drying unit 22 is capable of expelling requisite amounts of moisture during travel of the layer 50a along a relatively short drying station. This renders it possible to reduce the length of belts la- 1e and to thus further reduce the cost and the likelihood ofpremature damage to such belts.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of my contribution to the art.

What I claim as new and desired to be protected by Letters Patent is set forth in the appended claims.

l. in an apparatus for the production of webs of reconstituted tobacco wherein a conveyor including at least one endless travelling belt transports at least one layer of moist tobacco-containing material which is converted into at least one web of reconstituted tobacco upon expulsion of moisture therefrom, drying means for drying the layer of moist tobaccocontaining material, comprising at least one first chamber adjacent to the path of the layer, at least one second chamber adjacent to said first chamber, means for supplying heated air to said first chamber whereby such air expels moisture from successive increments of the travelling layer and is enriched with moisture, and means for drawing the thus enriched air into and from said second chamber.

2. Drying means as defined in claim 1, comprising a plurality of first and second chambers, said first chambers alternating with said second chambers.

3. Drying means as defined in claim I, wherein the means for supplying heated air to said first chamber comprises a heat exchanger and wherein the means for drawing enriched air into and from said second chamber comprises a device for admitting at least some of the thus withdrawn air into said heat exchanger.

4. Drying means as defined in claim 3, wherein said device comprises at least one blower having a suction side connected with said second chamber and a pressure side connected with said heat exchanger.

5. Drying means as defined in claim 4, further comprising means for admitting controlled amounts of atmospheric air to the suction side of said blower and means for discharging controlled amounts of air from the pressure side of said blower to the atmosphere.

6. Drying means as defined in claim 1, wherein said conveyor comprises several endless travelling belts having adjacent coplanar upper stretches which transport the layer past said chambers.

7. In an apparatus for the production of webs of reconstituted tobacco, a combination comprising conveyor means including a plurality of travelling endless belts having upper stretches; feeding means for supplying onto said upper stretches a moist tobacco-containing mass so that the mass forms a plurality of layers each of which travels with one of said belts, said feeding means having a. plurality of outlets, at least one for each of said belts, and each arranged to supply said mass onto the respective upper stretch; and drying means for expelling moisture from said layers to thereby convert the latter into at least one web of reconstituted tobacco.

8. A combination as defined in claim 7, wherein said upper stretches are immediately adjacent to and substantially coplanar with each other.

9. A combination as defined in claim 7, wherein said conveyor means further comprises roller means, said belts being trained over said roller means and said roller means comprising at least one roller common to all of said belts.

10. A combination as defined in claim 7, wherein said conveyor means further comprises common drive means for all of said belts.

11. A combination as defined in claim 7, wherein said feeding means comprises a single feeding unit arranged to supply moist tobacco-containing mass to all of said upper stretches.

12. A combination as defined in claim 7, further comprising cooling means for cooling the web of reconstituted tobacco downstream of said drying means.

13. A combination as defined in claim 7, further comprising moistening means for moistening the web downstream of said drying means.

14. A combination as defined in claim 7, further comprising removing means located downstream of said drying means and arranged to simultaneously strip the web ofi all of said belts.

15. A combination as defined in claim 7, further comprising separate tensioning means for each of said belts.

16. A combination as defined in claim 15, wherein each of said tensioning meanscomprises means for maintaining the respective belt under substantially constant tension.

17. A combination as defined in claim 15, wherein said belts further comprise lower stretches and wherein said tensioning means are adjacent to and tension the lower stretches of the respective belts.

18. In an apparatus for the production of reconstituted tobacco, a combination comprising conveyor means including a plurality of travelling endless belts having upper stretches; feeding means for supplying onto said upper stretches a moist tobacco-containing mass so that the mass forms at least one layer which travels with said belts, said feeding means comprising a plurality of compartments each accommodating a supply of moist tobacco-containing mass and each having an open lower end adjacent to one of said upper stretches, the lower ends of said compartments defining with the respective upper stretches elongated gaps for discharge of moist tobaccofor expelling moisture from said layer to thereby convert the latter into at least one web of reconstituted tobacco.

19. A combination as defined in claim 18, further comprising means for maintaining the supplies of moist tobacco-containing mass in said compartments at a predetermined level.

20. in an apparatus for the production of webs of reconstituted tobacco, a combination comprising conveyor means including a plurality of travelling endless belts having upper stretches; feeding means for supplying onto said upper stretches a moist tobacco-containing mass so that the mass forms at least one layer which travels with said belts; drying means for expelling moisture from said layer to thereby convert the latter into at least one web of reconstituted tobacco; removing means located downstream of said drying means and arranged to simultaneously strip the web off all of said belts; and heating means arranged to heat the web in the region of said removing means.

21. A combination as defined in claim 20, wherein one of said heating and removing means is located upstream of the other thereof.

22. In an apparatus for the production of webs of reconstituted tobacco, a combination comprising conveyor means including a plurality of travelling endless belts having upper stretches; feeding means for supplying onto said upper stretches a moist tobacco-containing mass so that the mass forms at least one layer which travels with said belts; drying means for expelling moisture from said layer to thereby convert the latter into at least one web of reconstituted tobacco; moistening means for moistening the web downstream of said drying means; and cooling means for cooling the web intermediate said drying means and said moistenin means.

In an apparatus for the production 0 webs of reconstituted tobacco, a combination comprising conveyor means including a plurality of travelling endless belts having upper stretches; feeding means for supplying onto said upper stretches a moist tobacco-containing mass so that the mass forms at least one layer which travels with said belts; drying means for expelling moisture from said layer to thereby convert the latter into at least one web of reconstituted tobacco; removing means located downstream ofsaid drying means and arranged to simultaneously strip the web off all of said belts; and air discharging means for directing jets of air against the web in the region ofsaid removing means. 

1. In an apparatus for the production of webs of reconstituted tobacco wherein a conveyor including at least one endless travelling belt transports at least one layer of moist tobaccocontaining material which is converted into at least one web of reconstituted tobacco upon expulsion of moisture therefrom, drying means for drying the layer of moist tobacco-containing material, comprising at least one first chamber adjacent to the path of the layer, at least one second chamber adjacent to said first chamber, means for supplying heated air to said first chamber whereby such air expels moisture from successive increments of the travelling layer and is enriched with moisture, and means for drawing the thus enriched air into and from said second chamber.
 2. Drying means as defined in claim 1, comprising a plurality of first and second chambers, said first chambers alternating with said second chambers.
 3. Drying means as defined in claim 1, wherein the means for supplying heated air to said first chamber comprises a heat exchanger and wherein the means for drawing enriched air into and from said second chamber comprises a device for admitting at least some of the thus withdrawn air into said heat exchanger.
 4. Drying means as defined in claim 3, wherein said device comprises at least one blower having a suction side connected with said second chamber and a pressure side connected with said heat exchanger.
 5. Drying means as defined in claim 4, further comprising means for admitting controlled amounts of atmospheric air to the suction side of said blower and means for discharging controlled amounts of air from the pressure side of said blower to the atmosphere.
 6. Drying means as defined in claim 1, wherein said conveyor comprises several endless travelling belts having adjacent coplanar upper stretches which transport the layer past said chambers.
 7. In an apparatus for the production of webs of reconstituted tobacco, a combination comprising conveyor means including a plurality of travelling endless belts having upper stretches; feeding means for supplying onto said upper stretches a moist tobacco-containing mass so that the mass forms a plurality of layers each of which travels with one of said belts, said feeding means having a plurality of outlets, at least one for each of said belts, and each arranged to supply said mass onto the respective upper stretch; and drying means for expelling moisture from said layers to thereby convert the latter into at least one web of reconstituted tobacco.
 8. A combination as defined in claim 7, wherein said upper stretches are immediately adjacent to and substantially coplanar with each other.
 9. A combination as defined in claim 7, wherein said conveyor means further comprises roller means, said belts being trained over said roller means and said roller means comprising at least one roller common to all of said belts.
 10. A combination as defined in claim 7, wherein said conveyor means further comprises common drive means for all of said belts.
 11. A combination as defined in claim 7, wherein said feeding means comprises a single feeding unit arranged to supply moist tobacco-containing mass to all of said upper stretches.
 12. A combination as defined in claim 7, further comprising cooling means for cooling the web of reconstituted tobacco downstream of said drying means.
 13. A combination as defined in claim 7, further comprising moistening means for moistening the web downstream of said drying means.
 14. A combination as defined in claim 7, further comprising removing means located downstream of said drying means and arranged to simultaneously strip the web off all of said belts.
 15. A combination as defined in claim 7, further comprising separate tensioning means for each of said belts.
 16. A combination as defined in claim 15, wherein each of said tensioning means comprises means for maintaining the respective belt under substantially constant tension.
 17. A combination as defined in claim 15, wherein said belts further comprise lower stretches and wherein said tensioning means are adjacent to and tension the lower stretches of the respective belts.
 18. In an apparatus for the production of reconstituted tobacco, a combination comprising conveyor means including a plurality of travelling endless belts having upper stretches; feeding means for supplying onto said upper stretches a moist tobacco-containing mass so that the mass forms at least one layer which travels with said belts, said feeding means comprising a plurality of compartments each accommodating a supply of moist tobacco-containing mass and each having an open lower end adjacent to one of said upper stretches, the lower ends of said compartments defining with the respective upper stretches elongated gaps for discharge of moist tobacco-containing mass onto the respective belts; and drying means for expelling moisture from said layer to thereby convert the latter into at least one web of reconstituted tobacco.
 19. A combination as defined in claim 18, further comprising means for maintaining the supplies of moist tobacco-containing mass in said compartments at a predetermined level.
 20. In an apparatus for the production of webs of reconstituted tobacco, a combination comprising conveyor means including a plurality of travelling endless belts having upper stretches; feeding means for supplying onto said upper stretches a moist tobacco-containing mass so that the mass forms at least one layer which travels with said belts; drying means for expelling moisture from said layer to thereby convert the latter into at least one web of reconstituted tobacco; removing means located downstream of said drying means and arranged to simultaneously strip the web off all of said belts; and heating means arranged to heat the web in the region of said removing means.
 21. A combination as defined in claim 20, wherein one of said heating and removing means is located upstream of the other thereof.
 22. In an apparatus for the production of webs of reconstituted tobacco, a combination comprising conveyor means including a plurality of travelling endless belts having upper stretches; feeding means for supplying onto said upper stretches a moist tobacco-containing mass so that the mass forms at least one layer which travels with said belts; drying means for expelling moisture from said layer to thereby convert the latter into at least one web of reconstituted tobacco; moistening means for moistening the web downstream of said drying means; and cooling means for cooling the web intermediate said drying means and said moistening means.
 23. In an apparatus for the production of webs of reconstituted tobacco, a combination comprising conveyor means including a plurality of travelling endless belts having upper stretches; feeding means for supplying onto said upper stretches a moist tobacco-containing mass so that the mass forms at least one layer which travels with said belts; drying means for expelling moisture from said layer to thereby convert the latter into at least one web of reconstituted tobacco; removing means located downstream of said drying means and arranged to simultaneously strip the web off all of said belts; and air discharging means for directing jets of air against the web in the region of said removing means. 